The primary goal is to determine whether or not polycyclic aromatic hydrocarbons (PAH) and their metabolic products in invertebrates are available for accumulation and re-metabolism by predatory fish. In vivo BP metabolism in the polychaete Nereis virens will be investigated using radiolabeled BP. Formation and residences times of phase 1 and phase 2 metabolites, and bound residues will be determined. Previous work has shown that Nereis can metabolize the PAH benz(a)anthracene extensively, with water soluble metabolites and bound residues being the primary products. Trophic transfer of BP and metabolic products from Nereis to the winter flounder Pseudopleuronectes americanus will then be investigated by characterization of in vivo BP metabolism in flounder fed: a) BP directly; b) worms exposed to PAH for only a short time (prior to extensive metabolism of BP), and c) worms exposed to BP for a sufficient time so that only metabolites and bound residues remain. The comparison between metabolite and adduct distribution in the fish as a function of these exposures should indicate whether or not fish can accumulate metabolites from worms, and whether or not the fish can re-metabolize conjugates and bound residues introduced through the diet. The influence of prior exposure to contaminated environments on the flounder's ability to accumulate and metabolize BP will also be determined. Transfer of BP metabolites from a member of the Capitella species complex to winter flounder will also be investigated, as Capitella can make up a major portion of the winter flounder diet locally. It is important to characterize the potential transfer of PAH metabolites in the aquatic environment because PAH reside primarily in sediments, and many benthic organisms can accumulate and metabolize PAH from sediments. Since metabolic activation is needed for PAH to express their mutagenic potential, characterization of its role in trophic transfer has significance to the health of fish and human consumers. This proposal will address the trophic transfer of BP a known carcinogen to the winter flounder, an important species in the New England sports fisheries which has been observed to show a high incidence of hepatic neoplasia in Boston Harbor.